A 1.5 V 8.3×10~(-6)/°C Digital Controlled CMOS Bandgap Voltage Reference

A novel digital controlled bandgap voltage reference is proposed in this paper. The adjustable voltage reference and temperature coefficient is implemented by controlling the number of PNP transistors. From a group of temperature curves controlled by digital control bits,a precise output reference voltage and temperature coefficient optimized curve can be obtained. The measurement indicates that the error of voltage reference can be controlled under ±4 mV,the best temperature coefficient achieves 8.3×10-6/°C from-40°C to 80°C,and the reference voltage varies only 1 mV with supply voltage from 1.5 V to 3.3 V. The proposed bandgap circuit is fabricated in a SMIC 0.18 μm CMOS process,and die area is 0.09 mm2.